“不断” is an extremely common and versatile word used in nearly all contexts, from everyday conversation to formal academic papers and government reports.
In Conversation: People use it to describe ongoing situations. For example, “这个月不断下雨” (It's been raining constantly this month) or “我的邻居不断地制造噪音” (My neighbors are constantly making noise).
In Business and Academia: It's frequently used to describe trends, development, and improvement. You will often see phrases like “不断创新” (continuous innovation), “不断提高” (unceasingly raise/improve), and “不断发展” (continuous development).
Connotation: The connotation is generally neutral-to-positive, especially when paired with positive verbs like “努力” (strive), “学习” (learn), or “进步” (progress). It can take on a slightly negative or complaining tone when describing an annoyance, such as a phone that is 不断地响 (constantly ringing).
Grammar Note: It is often followed by the particle 地 (de) before a verb, especially in written Chinese, to formally mark it as an adverb modifying the action, e.g., 不断地努力 (bùduàn de nǔlì). In spoken Chinese, the “地” is often omitted.